Biosynthesis of lysine in plants: evidence for a variant of the known bacterial pathways.

With the aim of elucidating how plants synthesize lysine, extracts prepared from corn, tobacco, Chlamydomonas and soybean were tested and found to lack detectable amounts of N-alpha-acyl-L,L-diaminopimelate deacylase or N-succinyl-alpha-amino-epsilon-ketopimelate-glutamate aminotransaminase, two key enzymes in the central part of the bacterial pathway for lysine biosynthesis. Corn extracts missing two key enzymes still carried out the overall synthesis of lysine when provided with dihydrodipicolinate. An analysis of available plant DNA sequences was performed to test the veracity of the negative biochemical findings. Orthologs of dihydrodipicolinate reductase and diaminopimelate epimerase (enzymes on each side of the central pathway) were readily found in the Arabidopsis thaliana genome. Orthologs of the known enzymes needed to convert tetrahydrodipicolinate to diaminopimelic acid (DAP) were not detected in Arabidopsis or in the plant DNA sequence databases. The biochemical and reinforcing bioinformatics results provide evidence that plants may use a novel variant of the bacterial pathways for lysine biosynthesis.

Identification of Acer rubrum using amplified fragment length polymorphism.

Amplified fragment length polymorphism (AFLP) analysis of botanical forensic evidence provides a means of obtaining a reproducible DNA profile in a relatively short period of time in species for which no sequence information is available. AFLP profiles were obtained for 40 Acer rubrum trees. Leaf material from five additional species was also typed. Genomic DNA was isolated using the DNeasy Plant Miniprep Kit (Qiagen, Valencia, CA), double-digested by two restriction endonucleases (EcoRI and MseI) and ligated to oligonucleotide adapters. Two consecutive PCR reactions (pre-amplification and selective amplification) were performed using a modification of the AFLP protocol described by Gibco (Invitrogen, Rockville, MD). The DNA fragments were separated by capillary electrophoresis using the CEQ 8000 DNA Fragment Analyzer. A number of Acer rubrum species-specific peaks were identified. In addition, within this closed set of samples, 15 of 16 (93.8%) blind samples were correctly identified. AFLP data can be used to determine the species of botanical evidence or to associate a sample to a source. This information can be used in forensic investigations to link a piece of evidence with a particular location or suspect.